Murder (also known as unlawful killing, felony murder or deliberate homicide) is the most serious form of a crime of homicide and it is punishable by death or life imprisonment. It is the most common criminal act in societies, with a large variety of possible motives. The study of this behavior is a subject of interest for psychologists, sociologists and criminologists. A lot of literature has been devoted to this issue but many of the findings are conflicting or generalizing. The reason for this may be that the homicidal behavior is complex and involves multiple variables, that cannot be studied separately or simply attributed to one factor.
In order to be prosecuted for murder, prosecutors must prove malice aforethought and the intent to kill or serious bodily injury or that the defendant knew the result was likely. However, the intent can be inferred from certain types of actions such as extreme recklessness and dangerous conduct. Some countries have civil-law codes that group all unjustified killings under a single category of murder while others, such as common law systems, distinguish between intentional and other felony murders on the one hand, and manslaughter and criminal negligence on the other.
Premeditated murder is the most obvious type of homicide and involves the killer planning the killing before carrying it out. It could involve buying rat poison at the store and placing it in the victim’s tea or a more sophisticated plan like putting cyanide in an auto’s gas tank or strangling the victim with a rope that was lying in wait.